1. Field of the Invention
The present invention relates to an automatic balancing apparatus for a balancing stand, which suspends and supports weights.
2. Description of the Prior Art
There conventionally exist balancing stands which suspend and support weights in optional positions in the air. For example, balancing stands capable of holding weights such as an operation microscope and auxiliary devices are used in the medical field (e.g. an Official Gazette of Japanese Patent Application Laid-open (kokai) No. 269463-1994). Balancing stands of the type generally have a structure in which a parallel linkage mechanism formed by a combination of a plurality of vertical arms and horizontal arms is supported at a predetermined fulcrum, an operation microscope and/or auxiliary devices is/are held at one end of the parallel linkage mechanism, and a counterweight is provided at the other end of the mechanism for balancing the weight relative to the operation microscope, etc.
A location of the balancing stand is selected to an optimum position according to the content of the operation to be performed, and balance adjustment is effected there. Since the auxiliary devices such as a side scope for an assistant doctor and a video camera are secured to the operation microscope, adjustment of whole balance is made by displacing the positions of the counterweight manually in accordance with the weight of the auxiliary devices.
However, positional adjustment of a counterweight has been made manually in a structural sense in the earlier technologies, so that balancing adjustment has not been effected so promptly. Further, since the parallel linkage mechanism moves to a large degree in unbalanced conditions, there is a possibility that the linkage mechanism may strike against some apparatus or the like present nearby. Under the circumstances, proposals of automatic balancing apparatuses applicable to the balancing stand of this kind have been waited. More specifically, proposals of automatic balancing apparatuses having a compact structure and applicable to the conventional balancing stands have been especially waited.
The present invention was accomplished in view of the earlier technologies, and its object is to provide an automatic balancing apparatus having a compact structure, capable of adjusting balance in an automatic and essentially prompt manner, and preventing arms from moving so substantially in unbalanced conditions.